'\" et
.TH ICONV_OPEN "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\"
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.\"
.SH NAME
iconv_open
\(em codeset conversion allocation function
.SH SYNOPSIS
.LP
.nf
#include <iconv.h>
.P
iconv_t iconv_open(const char *\fItocode\fP, const char *\fIfromcode\fP);
.fi
.SH DESCRIPTION
The
\fIiconv_open\fR()
function shall return a conversion descriptor
that describes a conversion from the codeset specified by the string
pointed to by the
.IR fromcode
argument to the codeset specified by the string pointed to by the
.IR tocode
argument. For state-dependent encodings, the conversion descriptor
shall be in a codeset-dependent initial shift state, ready for
immediate use with
\fIiconv\fR().
.P
Settings of
.IR fromcode
and
.IR tocode
and their permitted combinations are implementation-defined.
.P
A conversion descriptor shall remain valid until it is closed by
\fIiconv_close\fR()
or an implicit close.
.P
If a file descriptor is used to implement conversion descriptors, the
FD_CLOEXEC flag shall be set; see
.IR <fcntl.h> .
.SH "RETURN VALUE"
Upon successful completion,
\fIiconv_open\fR()
shall return a conversion descriptor for use on subsequent calls to
\fIiconv\fR().
Otherwise,
\fIiconv_open\fR()
shall return (\fBiconv_t\fP)\-1 and set
.IR errno
to indicate the error.
.SH ERRORS
The
\fIiconv_open\fR()
function may fail if:
.TP
.BR EMFILE
All file descriptors available to the process are currently open.
.TP
.BR ENFILE
Too many files are currently open in the system.
.TP
.BR ENOMEM
Insufficient storage space is available.
.TP
.BR EINVAL
The conversion specified by
.IR fromcode
and
.IR tocode
is not supported by the implementation.
.LP
.IR "The following sections are informative."
.SH EXAMPLES
None.
.SH "APPLICATION USAGE"
Some implementations of
\fIiconv_open\fR()
use
\fImalloc\fR()
to allocate space for internal buffer areas. The
\fIiconv_open\fR()
function may fail if there is insufficient storage space to accommodate
these buffers.
.P
Conforming applications must assume that conversion descriptors are not
valid after a call to one of the
.IR exec
functions.
.P
Application developers should consult the system documentation to
determine the supported codesets and their naming schemes.
.SH RATIONALE
None.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IR "\fIiconv\fR\^(\|)",
.IR "\fIiconv_close\fR\^(\|)"
.P
The Base Definitions volume of POSIX.1\(hy2017,
.IR "\fB<fcntl.h>\fP",
.IR "\fB<iconv.h>\fP"
.\"
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
.PP
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
